It is known to use check valves to allow fluid flow in one direction, and to prevent flow in the opposite direction. Check valves are used in a wide variety of applications, for example in air conditioning systems, for example in aircraft air conditioning systems.
Check valves commonly include a pair of valve elements or flappers located at an opening in a valve housing. The flappers are hingedly supported on a hinge pin mounted to the valve housing for rotation between a closed position in which they lie across and close the opening, preventing fluid flow through the opening in one direction and an open position in which, under the pressure of a fluid (gas or liquid) on one side of the check valve, the flappers rotate from their closed positions so as to allow the fluid to flow through the valve in the opposite direction.
In known check valve arrangements, a stop is provided to limit the rotational movement of the flapper elements as they open. In some arrangements, the stop comprises a stop pin which is mounted to mounting posts arranged on opposed sides of the valve housing opening. The stop pin is spaced from the opening such that when the flappers open, they engage the stop pin.
The flapper elements of such prior art flapper valves typically do not reach the fully open position simultaneously, and there is a slight delay between impacts. As the flapper elements typically open at high velocities and may impact the stop pin with considerable force, the stop pin and receiving posts themselves must be sufficiently robust to withstand the impact force of the flapper elements and to avoid the costly and time consuming process of replacing damaged parts. This may mean that the stop pin, hinge pin receiving posts and the flapper elements may have to be relatively heavy, which may have implications for example in aircraft applications.
The present disclosure relates to a check valve which includes a modified hinge pin and stop pin receiving post arrangement.